It would surprise me that sound quality gets worse not better or at least equal with each new generation. But like I said, I'm not a gamer, and I've never listened to any of these units. A review of the "special" PS1 saying it sounds "spectacular" doesn't mean a PS3 doesn't sound worse, equal, or better; it just doesn't say.
In A/V reproduction accuracy, there IS no concept of "accounting for personal taste/preference". As art consumers we don't "pick" the level of bass, nor the tint/brightness of a scene's sky, any more than we pick the ending of a novel or Mona Lisa's type of smile. "High fidelity" means "high truthfulness", faithful to the original artist's intent: an unmodified, neutral, accurate copy of the original master, ideally being exact and with no discernable alterations, aka "transparency".